Revert "vcl: StartPresentationMode should be using a sal_uInt32.."

This reverts commit 9321c560.

This is just plain wrong. Both the call sites and the function that this
method in turn calls want to use sal_Int32. It doesn't seem to cause any
actual problems, but that's probably just lucky.

Change-Id: Id77867094b9c7c209edd8b575c9203aee6515ff3
Reviewed-on: https://gerrit.libreoffice.org/54691Tested-by: Jenkins <ci@libreoffice.org>
Reviewed-by: Noel Grandin <noel.grandin@collabora.co.uk>

include/vcl/wrkwin.hxx

@@ -84,7 +84,7 @@ public:
 
     void            StartPresentationMode( bool   bPresentation,
                                            PresentationFlags nFlags,
-                                           sal_uInt32  nDisplayScreen );
+                                           sal_Int32  nDisplayScreen );
     /**
      @overload void StartPresentationMode( PresentationFlags nFlags, sal_uInt32 nDisplayScreen)
     */

vcl/source/window/wrkwin.cxx

@@ -160,7 +160,7 @@ void WorkWindow::StartPresentationMode( PresentationFlags nFlags )
     return StartPresentationMode( false/*bPresentation*/, nFlags, GetScreenNumber());
 }
 
-void WorkWindow::StartPresentationMode( bool bPresentation, PresentationFlags nFlags, sal_uInt32 nDisplayScreen )
+void WorkWindow::StartPresentationMode( bool bPresentation, PresentationFlags nFlags, sal_Int32 nDisplayScreen )
 {
     if ( !bPresentation == !mbPresentationMode )
         return;